Refrigerating system



A. F. SAWYER REFRIGERATING SYSTEM Filed July 28, 1925 Sept.. 20 1927.

. Patented sept. 2o, 1927. .A

UNITED- STATES ALBERT E. sAwYER, or navEnnILr., MASSACHUSETTS, AssTGNon To ravine L. i

KEITH, OF -HAVEIRHIIIQIIJ, MASSCHUSETT nEFn'rGEEATING SYSTEM. f'

Application led J-luly 28,1925. Serial No.46,582.

In providing automatic refrigeration'for apartments in a single building, where 1t 1s undesirable and unduly expensive to provide a complete refrigerating system for each apartment, it isn desirable to have the refrigerant supplied automatically by` apsingle motor driven compressor when a system of the compressor, condenser, expander type of l'sonably satisfactory when employedin connection with refrigerating units ofv large-.capacity which are under direct supervlsion or control, particularly when the units are placed at nearly the samev level, and, while,

theoretically, lthe Adesired result of a satisfactory system, which is entirely automatic, may be secured by means of various forms of automatic valves designed .to control the supply of refrigerant from the main pipe to theunitaccording to predetermined requlrements, yet, so far asl I am aware, these systems have been found to be unsatisfactory,

particularly because some of the units were liable to be linsuiciently supplied with liquid refrigerant, this diiiiculty being particularly great when the refrigerating units were locatedl at different elevations.

The object of my invention/ is to provide a refrigerating system of the vtype above referred to lin which a-series of refrigerating units may be effectively supplied by a single I compressor, the temperature in each unit of which Iis to be naintained ata predetermined mean point, whatever `the requirements, within reasonable limits, which are placed thereon, and the system to be adapted to permit any one of the units to be cut out of the system without disturbing the operation of the other units.

In this connection, another object of the 'invention is to provide a system in which `the ent-rance, to any substantial extent, of

refrigerant in gaseous form to the coolin tank, or expansion chamber, is prevente and the entrance of liquid refrigerant only is permitted. i y

I accomplish t se objects by providing, in `connection w th any ordinary form of motor driven compressor, a series of surface condensers, orA condensing coils correspond-` ing in number to the number of e ansion units to be supplied, connecting sald coils to each other and to the discharge port of the compressor at their inlet ends separately connecting each coil at its discharge end to the expansion chamber of the corresponding cooling unit through an automatic apparatus which prevents the passage of gaseous refrigerant and permits the passage of liquid refrigerant thereto,- underA certain conditions,

connecting the outlet from each expansion chamber to the inlet of the compressor, and

:by providing, in connection therewith, a

single regulating means for the motor for .driving the, compressor, so that when the pressure of the refrigerant at the inlet to the compressor is raised to a certain point, the motor will be started, and, when it is .lowered to a certain point, the motor will be stopped.

F or a more complete and detailed desoripl tion of the system embodying my invention reference is made to the accompanying drawing in which:

Fig. lis a diagrammatical view of a closed circult refrigerating system embodying my invention, and

Fig. 2 is a detail view of a compressor and condenser connection which I may employ. y

Figs. 3 and 4 are detail sectional views of an' inlet control device for the expansion chambers which Iv employ and Fig. 5 is a detail `view of a form-of valve -which is employedl in connection therewith.

As certain apparatus, whichA is employed in connection with the refrigerating system hereinafter described, is well known in systems 'of the type above indicated, such apparatus has been conventionally illustrated.

, As indicated, the motor 1 hasamain shaft, on which a cooling fan 3 is mounted, said shaft being arranged to operate a com-l pressor pump 4, from which a discharge pipe 5 leads.

According to' my invention, I provide ,a plurality of surface condensers or condenser coils 6, 7, 8 corresponding in number to the particular number of independent refrigerating units to be emplo ed, the particular number `of units shown p ing merely illustrative, and connect the upper orinlet end I .of each coilto a `casing 9, into which the discharge pipe from the compressor also opens, so that each condenser coil is in open communication with the others and with the discharge pipe from the compressor, at its inlet end, and extends downwardly to its outlet from this point. f

A corresponding plurality of refrigerating units are provided, each of which, comprises an expansion chamber or refrigerant tank, as 10, 11 and 12, and as said tanks will, in practically all instances, be located at a higher elevation than the condenser coils, the system being of special advantage in such a relation, they are so indicated in the drawing. The tanks are respectively connected to the lower, or outlet ends of the corresponding coils 6, 7, and 8 by conducting pipes 13, 14 and 15, the connection thereto in each instance being made through an automatically controlled valve, which is illustrated in detail in Figs. 3, 4, and 5, and

which I have especially designed for the purpose, the same form of valve device being employed for each refrigerating unit.

The device comprises a container 16 having a cover 17, which has a gas tight connection therewith, said cover having an inlet,

passage 18 and outlet passage 19, said inlet passage opening to the container close to the side wall thereof and having a conduct ing pipe, as 13, connected thereto, and said outlet passage being connected to an eX- pansion `tank by a. pipe 20. A pipe 21 is connected to the cover 17, in communication with the outlet passage 19, and depends therefrom, the lower end of said pipe being open and a valve seat 22 being provided in the passage 19. A metal cup 23 is provided within the container and is mounted to tilt therein on a pivot 24, which, for convenience, is supported by the pipe 21 at its lower end. A needle valve 25 is connected by a Ypivot pin 26 to ,the bottom of the cup 23 and eX- tends upward in the pipe 21 into position to seat against the seat 22, when the cup is in its horizontal position. The conical upper end of the needle valve 25 is provided with a leak passage 27, for purposes to be explained, and as indicated in detail in Fig. 5. Return pipes 28, 29 and 30 are respectively connected to the top portions of the tanks 10, 11 and 12, said pipes being in turn connected to a single return pipe 31 which leads to the intake end of the compressor, so that a closed liuid circuit is formed through each tank. A pressure regulator 32 is provided in the return pipe 3l, which is arranged to operate the control switch of the motor, so that, when the gas pressure varies to a piedetermined extent from normal the motor will be started or stopped as the case may be. That is, when the gas pressure of the refrigerant in the refrigerating tanks is at a certain point, the temperature of theliquid refrigerant therein will beat a certain point,

as possible.

and, as the gas containing chambers in each tank are all connected to the common return pipe, the gas pressure in all the tanks and in the return pipe will be practically the same. The temperature of the liquid refrigerant in all the tanks will consequently be the same, and any increase in gas pressurein any one of the tanks will be immediately transmitted to all the other tanks and to the return pipe, so that when this pressure is raised above the predetermined limit, the motor will be started, and, when the pressure is lowered to the desired extent, the motor will be stop d.

Suitable shut-off valves 33 will be provided at the inlet end of each condensing coil, and in the discharge pipe of each expansion tank, so that,wvheny use of any one of the refrigerating units is to be discontinued, the corresponding valves 33 will be closed, and the normal operation of the other units will not be interfered with, operation being resumed in the unit by merely opening these valves.

When the system is to be started each refrigerating tank will be filled wit-h a suitable quantity of liquid refrigerant, as methyl chloride, and the other portions of the system will be filled with gaseous refrigerant, all air being expelled from the system as far The shut-off valves having been opened, the operation is as follows:- i

In the normal operation of the system, when, by reason of increase in temperature of the refrigerant in the expansion tanks, and consequent increase of gas pressure therein, and in the return pipe 31, the motor is started, the action of the compressor in forcing gaseous refrigerant into all ofthe condenser coils will be the same, as their inlet ends are all in open communication with the discharge pipe of the compressor and with each other. All the coils are arranged so that they are practically under the influence of the cooling means, which, as herein shown, is an air cooling means, but

which, obviously, may be any other suitable p means, although the air cooling means is preferred, one of the advantages of the present system residing in the fact that it enables the use of an air cooling system.

By the action of the compressor, the gas pressure will be raised uniformly in all the condenser coilsand all the containers 16 and the pipes connecting the coils and the containers.

While, in starting up the system originally, no liquid refrigerant may be contained in the cups 23, so that gas may pass from the containers 16 to the ie'tiigerating tanks, yet the size of the outlet passages 19 from the containers is relatively small, as coinpared with the volume of gas delivered by the compressor, so that pressure will be ini'- mediately built up inthe containersto an extent sufficient to cause the condensing operation to begin, and condensation to take place in all the coils, containers and connecting pipes. The liquid formed in the coils lwill accumulate in the lower portions theretherethrough will not bedischarged directly into the cup 23, but only into the container at one side thereof, so that, as the condensing process continues, the container will be filled until the cup\23 is lifted by its buoyancy to its horizontal position shown in Fig. 4, closing the valve 25. The container will then be filled until the liquid overflows into the cup 23 and fills the same to such an extent that its buoyancy is insuflicient to sustain it in the position of Fig. 4, so that it swings i down to the tilted position of Fig. 3. thereby opening the valve 25, and permitting the gas pressure-on the surface of the liquid in the cup to cause the liquid therein to be forced up the pipe 21 through pipe 20 into the expansion tank to which it is connected. This will continue until the cup is emptied to such an extent that its buyonacy is suilicient to restore it to its initial, or horizontal position and close valve 25. As at this time the container will be filled to the level of the edge of the cup, indicated by the line X in Fig. 3, the cup will be lifted by its buoyancy by the time the liquid level therein has been lowered approximately to the level of line y in Fig. 3, so that the lower end of the pipe 21 at no time will become unsealed. If the opera- 4 tion of the compressor is continued. thev container will be filled again until the liquid overflows into the cup again, so that it sinks and the above described operation is repeated.

This operation will continue until the deciency of liquid refrigerant has been supplied andthe temperature thereof has been reduced by reason of lthe reduction in pressure of the gas in the refrigerating tanks, caused by the suction "action of the compressor. As thev action of the compressor in forcing gas into the condenser coils is unis form, the quantity of liquid refrigerant supplied to each refrigerating tank will be practically constant` and. as Ithe temperature of the refrigerant in each tank will be the same, by reason of the uniform gas pressure therein', Athe refrigerating effect of all the tanks will be practically the same. This is assuming that the tanks are of approximately uniform size, but i-f one tank was considerably larger than the rest and the demands thereon were correspondingly greater the capacmined point and then the pressure regulator will automatically open the switch and stop the motor. When the motor stops the pressure in the supply side to the tanks will be considerably greater,than that in the return side, so that, ordinarily, this pressure will be sufficient to force liquid-remaining inthe cups 23 up the pipes 21 until the cups lift by their buoyancy and close valves 25. The leak passage 27, which is provided in each valve, permits the liquid remaining in the cup, to be forced therefrom until the pipe 21 becomes unsealed and then gas and liquid will be ermitted to escape past valve 25 into the tan s until the pressure in the supply and return sidesA of the system is equalized, the quantity of gas thus escaping being practically. insignificant. This is an advantageous feature of my invention, as the pressure on each side of the compressor `will thus be equalized within a few minutes after the motor stops, so that when the motor is started again the load thereon will be practically nothing more than friction. lThis enables a motor of low torque to be employed, which has important advantages. Also, in filling the system, while it is the intention to remove the air therein as completely as possible, yet, to do this is somewhat diflicult, so

that a substantial quantity of 4air is fret quently left therein, and if the refrigerant gas is somewhat heavier thanv air, any air in the system is liable to accumulate in the highest portion thereof, .particularly in the uppermost container.- Under such yconditions the container might be filled with liquid refrigerant suliicientlyto lift the cup therein and close the needle valve, and then, if the portion of the container above the liquid level were filled with air and the valve was tightly closed, the air would prevent theentrance of more refrigerant so that circulation through theunit would be prevent ed. By providing the leak passage 27, air

accumulating in a container l16 will be per-- mitted to escape tothe return side of the circuit, so that it will notfmateriallyinterfere with the operation' of the system.

The above described apparatus is advantageous over the ordinary expansion valve for admitting refrigerant to the refrigerating tanks, in that such valves are liable to permit the passage of gas vwith the liquid to the refrigerating tanks which is the'cause of substantial waste, and if such valves become leakyfurther waste is caused, as the ordinary expansion valve must close tightly in order to operate eiiiciently.v It is practically impossible for a supply apparatus for the lll lia

tanks such as above described to get out of order while the ordinary expansion valve is liable to become inoperative.

lVith thepabove described construction the supply of liquid refrigerant to each refrigerating tank 1s practically uniform, for the reason that the supply of gaseous refrigerant to each pipe which conducts the refrigerant thereto is constant, and this distribution would not be uniform if it were made after the refrigerant begins to liquefy. As the expansion chambers of all the chambers are connected so that the pressure therein is uniform, any increase of pressure in any one tank is immediately transmitted to the others, so that each tank may act as a reserve for the others and as the pressure and quantity of liquid refrigerant in each tank is uniform the temperature therein will be kept uniform.

While the refrigerating units in the above described system are illustrated as located at different elevations above the compressing and condensing apparatus, under which conditions it is particularly advantageous, it is to be understood that it would be equally advantageous if the compressing and condensing apparatus were located above the refrigerating units. However conditions where such an arrangement would be desirable are very unusual. The system is also advantageous where all the units are on the same levelas the said apparatus, but the difficulties of single pipe distribution under such conditions are not as great as when the units are at different levels. It will also be understood, that, while the particular form of apparatus above described, for admitting liquid and preventing the passage of gas to the expansion tanks, is considered to be especially advantageous in the above described system, yet it will operate satisfactorily when used in connection with types of expansion valves which employ a oat in the expansion tank for regulating the supply of liquid refrigerant thereto.

I claim:

1. A refrigerating system comprising a plurality of refrigeratingV expansion chamers adapted to contain a refrigerant, a corresponding plurality of surface condensers, a separate connection between the discharge end of each condenser and its corresponding expansion chamber, a compressor having its discharge in open communication with the inlet end of each condenser and return con` nections placing said expansion chambers in open communication with each other and with the inlet to the compressor, forming a closed fluid circuit through each condenser and corres ending chamber.

2. A re rigerating system comprising a plurality of refrigerating expansion chambers adapted to contain a refrigerant, a corresponding plurality of surface condensers, a

separate connection between the discharge end of each condenser and its corresponding expansion chamber, a compressor having its discharge in open communication with the inlet end of each condenser, return connections placing'said expansion chambers in open communication with each other and with the inlet tothe compressor, forming a closed fluid circuit through each chamber, a motor for operating said compressor, and a pressure regulator for controlling said motor according to the gas pressure in said return connections.

3. A refrigerating system comprising a plurality of refrigerating expansion chambers adapted to contain a refrigerant, a corresponding plurality of surface condensers, a compressor having its discharge connected to the top portion of each condenser land arranged to supply gaseous refrigerant thereto in equal volume, return pipes arranged to place said expansion chambers in open communication with each other and to connect the same to the inlet to the compressor, a closed container arranged adjacent each expansion chamber, a. separate conduc-- tor pipe connected to the bottom portion of each condenser and extending to a corresponding container in open .communication therewith, and connections between each container and the adjacent expansion chamber` including automatic means normally permitting the passage of liquid from the container to the chamber and preventing' the passage of gas thereto.

4. A refrigerating system comprising a plurality of refrigerating expansion chambers adapted to contain a refrigerant. a corresponding plurality of surface condensers, a compressor having its discharge connecti ed to the top portion of each condenser and arranged to l supply gaseous refrigerant thereto in equal volume, return pipes arranged to place said expansion chambers in open communication with each other and to connect the same to the inlet to the compressor, a closed container arranged adjacent each expansion chamber, a separate conductor pipe connected to the bottom portion of each condenser and opening into the upper portion of its corresponding container, an outlet pipe opening to the bottom portion Y of each container and into the adjacent ex# pansion chamber, and means for normally sealing the inlet to each outlet pipe including a valve arranged to close thesame to prevent unsealing and to o en the same when the container is filled with liquid to a. predetermined extent, to permit the liquid to be forced into the expansion chamber.

5. A refrigerating system comprising a lplurality of refrigerating expansion chamers adapted to containarefrigerant,acorrespending plurality of surface condensers, a compressor having its discharge connected to lll.l

- the top portion of each condenser and ar- Cil,

ranged to supply gaseous refrigerant thereto in equal volume, return pipes arranged to place said expansion chambers in open com-I munication with each other and to connect the same to the inlet to the compressor, a. closed container arranged adjacent each expansion chamber, a separate conductor pipe connected to the bottom portion of each condenser and` opening into the upper portion of its corresponding container, an outlet pipe opening to the bottom portion of each container and'into the adjacent expansion chamber, and means for normally sealing the inlet to each outlet pipe including a valve arranged to close the same to prevent unsealing and to open the same when the container is filled With liquid to a predetermined extent, to permit the liquid to be forced into the expansion chamber, said -means including means to permit gradual escape of iuid from the container to its eX- pansion chamber, for the purposes described.

6. A refrigerating system comprising a plurality of refrigeratingv expansion chambers adapted to contain a refrigerant,a corresponding plurality of surface condensers, a compressor having its discharge connected'to the top portion of each condenser andarranged to supply gaseous refrigerant there,-y to in equal volume, 'ret1'1r1i-l vpipes arranged to place said expansion cham ers in open communication Awith-each other and to connect` the same to the'inlet to the compressor, 'a closed container arranged adjacent each expansion chamber, a separate Conductor pipe connected to the bot-tom portion of each condenser'and opening into the upper portion of its corresponding container, an outlet pipe opening tothe bottom portion of each `container and into the adjacent expansion chamber, means for normally sealing the inlet to each outlet pipe, including a cup movably mounted in the container to be raised by its buoyancy and lowered by its gravity when filled With liquid overflowing from the container, and into the bottom portion of which the outlet pipe opens, and a valve arranged 

